1. anonymous

well first we need $$\frac{42}{3}=14$$ to know which term we want

2. anonymous

so it is either the 14th term or the second term depending on how you are counting. makes no difference. the term looks like $\dbinom{16}{2}(x^3)^{14}(-3)^2$

3. anonymous

$\dbinom{16}{2}=\frac{16\times 15}{2}=8\times 15=120$ and $$(-3)^2=9$$ multiply to get your answer

4. anonymous

wow my drawing really sucked.... oh well!!

5. anonymous

Thanks so much satellite73!